<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>计算属性与监视</title>
  <script src="vue.js"></script>
</head>
<body>
<div id="root">
  姓：<input type="text" v-model="firstName"><br>
  名: <input type="text" v-model="lastName" ><br>
  全名: <span>{{forname()}}</span>
</div>
</body>
<script type="text/javascript">
  new Vue({
    el:'#root',
    data:{
      firstName:'张',
      lastName:'三',
    },
    methods:{
      forname(){
        return this.firstName+'--'+this.lastName
      }
    }
  })
</script>
</html>